/******************************************************************************
 * Filename : uc_md5.c
 * Created  : 2009-11-24 by franco.yin
 * Description -
 *
 ******************************************************************************/

#ifdef __cplusplus
extern "C" {
#endif

#include "uc_md5.h"

#define MD 5

/* UINT4 defines a four byte word */
typedef UC_U32 UINT4;

typedef struct ucmd5_ctx{
  UINT4 state[4];                                   /* state (ABCD) */
  UINT4 count[2];        /* number of bits, modulo 2^64 (lsb first) */
  unsigned char buffer[64];                         /* input buffer */
}ucmd5_ctx_s;

static unsigned char PADDING[64] = {
  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/* F, G, H and I are basic MD5 functions. */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits. */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
 */
#define FF(a, b, c, d, x, s, ac) {\
 (a) += F ((b), (c), (d)) + (x) + (UINT4)(ac);\
 (a) = ROTATE_LEFT ((a), (s));\
 (a) += (b);\
  }
#define GG(a, b, c, d, x, s, ac) {\
 (a) += G ((b), (c), (d)) + (x) + (UINT4)(ac);\
 (a) = ROTATE_LEFT ((a), (s));\
 (a) += (b);\
  }
#define HH(a, b, c, d, x, s, ac) {\
 (a) += H ((b), (c), (d)) + (x) + (UINT4)(ac);\
 (a) = ROTATE_LEFT ((a), (s));\
 (a) += (b);\
  }
#define II(a, b, c, d, x, s, ac) {\
 (a) += I ((b), (c), (d)) + (x) + (UINT4)(ac);\
 (a) = ROTATE_LEFT ((a), (s));\
 (a) += (b);\
  }

/* Constants for ucmd5_transform routine. */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

/* Encodes input (UINT4) into output (unsigned char). Assumes len is
  a multiple of 4.
 */
static void
ucmd5_encode(unsigned char *output, UINT4 *input, unsigned int len)
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[j] = (unsigned char)(input[i] & 0xff);
		output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
		output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
		output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
	}
}

/* Decodes input (unsigned char) into output (UINT4). Assumes len is
  a multiple of 4.
 */
static void
ucmd5_decode(UINT4 *output, unsigned char *input, unsigned int len)
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |
		(((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
	}
}

/* MD5 basic transformation. Transforms state based on block.
 */
static void
ucmd5_transform(UINT4 state[4], unsigned char block[64])
{
	UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	ucmd5_decode(x, block, 64);

	/* Round 1 */
	FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
	FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
	FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
	FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
	FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
	FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
	FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
	FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
	FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
	FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
	FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
	FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
	FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
	FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
	FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
	FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

	/* Round 2 */
	GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
	GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
	GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
	GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
	GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
	GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
	GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
	GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
	GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
	GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
	GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
	GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
	GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
	GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
	GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
	GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

	/* Round 3 */
	HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
	HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
	HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
	HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
	HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
	HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
	HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
	HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
	HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
	HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
	HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
	HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
	HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
	HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
	HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
	HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

	/* Round 4 */
	II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
	II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
	II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
	II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
	II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
	II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
	II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
	II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
	II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
	II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
	II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
	II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
	II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
	II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
	II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
	II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;

	/* Zeroize sensitive information.
	*/
	memset(x, 0, sizeof (x));
}

/* MD5 initialization. Begins an MD5 operation, writing a new context. */
void
ucmd5_init(ucmd5_ctx_s *context)
{
	context->count[0] = context->count[1] = 0;
	context->state[0] = 0x67452301;
	context->state[1] = 0xefcdab89;
	context->state[2] = 0x98badcfe;
	context->state[3] = 0x10325476;
}

/* MD5 block update operation. Continues an MD5 message-digest
  operation, processing another message block, and updating the
  context. */
void
ucmd5_update(ucmd5_ctx_s *context, unsigned char *input,unsigned int inputLen  )
{
	unsigned int i, index, partLen;

	/* Compute number of bytes mod 64 */
	index = (unsigned int)((context->count[0] >> 3) & 0x3F);

	/* Update number of bits */
	if ((context->count[0] += ((UINT4)inputLen << 3)) < ((UINT4)inputLen << 3)) {
		context->count[1]++;
	}
	context->count[1] += ((UINT4)inputLen >> 29);

	partLen = 64 - index;

	/* Transform as many times as possible.
	*/
	if (inputLen >= partLen) {
		memcpy(&context->buffer[index], input, partLen);
		ucmd5_transform (context->state, context->buffer);

		for (i = partLen; i + 63 < inputLen; i += 64) {
			ucmd5_transform(context->state, &input[i]);
		}

		index = 0;
	} else {
		i = 0;
	}

	/* Buffer remaining input */
	memcpy(&context->buffer[index], &input[i], inputLen-i);
}

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
  the message digest and zeroizing the context.*/
void
ucmd5_final(unsigned char digest[16], ucmd5_ctx_s *context)
{
	unsigned char bits[8];
	unsigned int index, padLen;

	/* Save number of bits */
	ucmd5_encode(bits, context->count, 8);

	/* Pad out to 56 mod 64. */
	index = (unsigned int)((context->count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	ucmd5_update(context,(unsigned char*) PADDING, padLen);

	/* Append length (before padding) */
	ucmd5_update(context, bits, 8);
	/* Store state in digest */
	ucmd5_encode(digest, context->state, 16);

	/* Zeroize sensitive information.
	*/
	memset(context, 0, sizeof(*context));
}

/* Digests a string and prints the result.
 */
char*
ucmd5_bin(char *pDst, char *pSrc, int src_len)
{
	ucmd5_ctx_s context;
	unsigned char digest[16];
	char output[35];
	int i = 0;

	ucmd5_init(&context);
	ucmd5_update(&context, (unsigned char*)pSrc, (unsigned int)src_len);
	ucmd5_final(digest, &context);

	for (i = 0; i < 16; i++) {
		sprintf(output + (2 * i), "%02x", (unsigned char)digest[i]);
		sprintf(output + (2 * i + 1), "%02x", (unsigned char)(digest[i]<<4));
	}
	memcpy(pDst, output, UCMD5_LEN);

	return pDst;
}

char*
ucmd5_bin_key(char *pDst, char *pSrc, int src_len, char *pKey)
{
	char digest[16];
	char output[35];
	ucmd5_ctx_s context;
	ucmd5_ctx_s tctx;
 	unsigned char k_ipad[65];
	unsigned char k_opad[65];
	unsigned char tk[16];
	int i = 0;
	int text_len = src_len;
	int key_len = strlen(pKey);

	/* if key is longer than 64 bytes reset it to key=MD5(key) */
	if (key_len > 64) {
		ucmd5_init(&tctx);
		ucmd5_update(&tctx,(unsigned char*)pKey, key_len);
		ucmd5_final(tk, &tctx);

		pKey = (char*)tk;
		key_len = 16;
	}

	for(i=0;i<65;i++) {
		k_ipad[i]=(unsigned char)0;
	}
	for(i=0;i<65;i++) {
		k_opad[i]=(unsigned char)0;
	}

	for(i=0;i<key_len;i++) {
		k_ipad[i]=(unsigned char)pKey[i];
		k_opad[i]=(unsigned char)pKey[i];
	}

	/* XOR key with ipad and opad values */
	for (i=0; i<64; i++) {
		k_ipad[i] ^= 0x36;
		k_opad[i] ^= 0x5c;
	}

	ucmd5_init(&context);                   /* init context for 1st pass */
	ucmd5_update(&context, k_ipad, 64);      /* start with inner pad */
	ucmd5_update(&context, (unsigned char*)pSrc, text_len); /* then text of datagram */
	ucmd5_final((unsigned char*)digest, &context);          /* finish up 1st pass */

	ucmd5_init(&context);                   /* init context for 2nd pass */
	ucmd5_update(&context, k_opad, 64);     /* start with outer pad */
	ucmd5_update(&context,(unsigned char*) digest, 16);     /* then results of 1st hash */
	ucmd5_final((unsigned char*)digest, &context);          /* finish up 2nd pass */

	for (i = 0; i < 16; i++) {
		sprintf(output + (2 * i),"%02x",(unsigned char)digest[i]);
		sprintf(output + (2 * i + 1),"%02x",(unsigned char)(digest[i]<<4));
	}
	memcpy(pDst, output, UCMD5_LEN);

	return pDst;
}

/* Digests a file and prints the result.
 */
char*
ucmd5_file(char *pDst, char *filename)
{
	FILE *file = NULL;
	ucmd5_ctx_s context;
	unsigned char buffer[1024], digest[16];
	char output[35];
	int len = 0;
	int i = 0;

	memset(pDst, 0, UCMD5_LEN);
	if ((file = fopen (filename, "rb")) == NULL) {
		uc_err("%s can't be openedn", filename);
		return pDst;
	} else {
		ucmd5_init(&context);
		while ((len = fread (buffer, 1, 1024, file))) {
			ucmd5_update(&context, buffer, len);
		}
		ucmd5_final(digest, &context);
		fclose (file);

		for (i = 0; i < 16; i++) {
			sprintf(output + (2 * i),"%02x",(unsigned char)digest[i]);
			sprintf(output + (2 * i + 1),"%02x",(unsigned char)(digest[i]<<4));
		}
		memcpy(pDst, output, UCMD5_LEN);

		return pDst;
	}
}

#ifdef __cplusplus
}
#endif
